D5 (D5244T to 2005) Ecm 6805 & 2503

[mtyardley]

I have Engine System Service Required permanently displayed with fault codes 6805 & 2503. I had been getting intermittent limp mode but this seems to have resolved itself more or less. Car seems to pull well in all gears can spin wheels in 2nd and DSTC illuminates even manages to accelerate up hill.

Cruise control has ceased to function and I get a whistling noise from turbo I think especially when cold. There is also a distinct whoosh of air (waste gate like) when changing gear under hard acceleration. I can clear the codes and the Engine System Service Required goes out I can start the car and the warning does not return until I start to move.

So far I have changed the Fuel Filter.
Checked Engine Mounts both hold a vacuum.
Vacuum pump is putting out 22Hg at idle.
The thingy on the air box isolates the engine mounts at 1100rpm.
The Engine Mounts are receiving vacuum below 1100rpm.
The other thingy bolted to the engine is supplying the turbo actuator thingy 22Hg at idle which increases with revs up to 38hg ish at 2500 to 3000rpm then drops back a little from 3000rpm + ?
Got under the car and put vac pump directly on the turbo actuator thing and the arm moved 3cm or so initially perhaps a little sticky seemed to click a little as drawing down a vacuum.
No observable obvious leaks from inter cooler which was changed at 96k now at 132k. Hoses appear to be intact and fresh air hose although squeezable it does not seem really soft (although not sure how firm it should be).
I checked the PCV thingy and tubes are all clear it seems.

I'm really drawing a blank with this one now does anyone have any clues as what to try next. Is the lack of Cruise Control a clue? Low fuel pressure as well the in tank pump is audible prior to start up and the car starts within a couple of turns?